all: fix lint warnings (#7016)

core/src/main/java/io/grpc/inprocess/InProcessChannelBuilder.java

@@ -193,7 +193,7 @@ public final class InProcessChannelBuilder extends
     private final boolean useSharedTimer;
     private final int maxInboundMetadataSize;
     private boolean closed;
-    private boolean includeCauseWithStatus;
+    private final boolean includeCauseWithStatus;
 
     private InProcessClientTransportFactory(
         String name,

core/src/test/java/io/grpc/internal/AbstractTransportTest.java

@@ -2067,7 +2067,7 @@ public abstract class AbstractTransportTest {
    * Verifies that the client status is as expected. By default, the code and description should
    * be present, and the cause should be stripped away.
    */
-  private void checkClientStatus(Status expectedStatus, Status clientStreamStatus) {
+  private static void checkClientStatus(Status expectedStatus, Status clientStreamStatus) {
     assertEquals(expectedStatus.getCode(), clientStreamStatus.getCode());
     assertEquals(expectedStatus.getDescription(), clientStreamStatus.getDescription());
     assertNull(clientStreamStatus.getCause());

interop-testing/src/main/java/io/grpc/testing/integration/GrpclbFallbackTestClient.java

@@ -172,7 +172,7 @@ public final class GrpclbFallbackTestClient {
     }
   }
 
-  private void runShellCmd(String cmd) throws Exception {
+  private static void runShellCmd(String cmd) throws Exception {
     logger.info("Run shell command: " + cmd);
     ProcessBuilder pb = new ProcessBuilder("bash", "-c", cmd);
     pb.redirectErrorStream(true);

rls/src/main/java/io/grpc/rls/RlsProtoConverters.java

@@ -189,4 +189,6 @@ final class RlsProtoConverters {
       return new GrpcKeyBuilder(names, nameMatchers);
     }
   }
+
+  private RlsProtoConverters() {}
 }